The present invention relates to a two-way combination optical system unit used for a receptacle-capable optical transceiver.
Heretofore, a two-way combination optical system unit is constituted, e.g., for the use of a receptacle-capable optical transceiver. As described above, an optical transceiver in which a transmitting function is integrated with a receiving function is widely employed in a field of data communication wherein optical fibers are used. Particularly, as described in xe2x80x9cOPTCOMxe2x80x9d (the April 1998 issue, page 60), a development for a receptacle-capable compact optical transceiver compliant with a small size twine core array terminal (for example, MT ferrule specified in IEC874-16) has been pursued.
On one hand, there is an optical system unit wherein an optical semiconductor device is mounted on an Si substrate, and further fibers are mounted in V-grooves defined on the Si substrate, whereby the optical semiconductor device is optically coupled with the fibers. A structure of such optical system unit is shown in Kurata et al. xe2x80x9cDevelopments in Surface-mount Optical Modulexe2x80x9d (lecture number SC-1-12) in a collection of lectures in the great meeting of electronics society in the ""95 Institute of Electronics, Information and Communication Engineers.
In the case where this optical system unit is applied to the above described receptacle-capable compact optical transceiver, a fiber distance in an MT ferrule is 0.75 mm and it is very narrow. Thus, it is difficult to mount two V-grooves as well as light-emitting and light-receiving semiconductor devices onto the same Si substrate, because the structure becomes complicated. Moreover, there is also such a problem that since a distance defined between a transmitting section and light-receiving section is close to each other, electrical crosstalk occurs easily.
Heretofore, to solve the above described problem, an optical connector is optically connected with an optical system unit through a polymer light waveguide for adjusting distance as described in IEEE Proceedings of the 46th Elec., Comp. and Tech. Conf., K. H. Hahn et al. (pp. 301-307).
In this respect, however, the number of parts and the number of manufacturing man-hours increase, besides one more position to be connected increases in the above described conventional manner. In addition, there is also a negative problem where there is no effect for improving electrical crosstalk.
Accordingly, an object of the present invention is to provide a two-way combination optical system unit which results in a less number of parts and manufacturing man-hours, besides resulting in low connection loss.
According to the feature of the invention, a two-way combination optical system unit, comprises:
a light emitting element mounted on a side of a first prescribed substrate on which a V-shaped groove has been defined,
a light receiving element mounted on a side of a second prescribed substrate on which a V-shaped groove has been defined, and
a molded optical connector in which an optical fiber for light transmission connected to the light emitting element is molded integrally with an optical fiber for light reception connected to the light receiving element, and end surfaces of the optical fibers are exposed on a side surface thereof to be served for light transmitting and receiving ends.
In the preferred embodiment, the side of the first prescribed substrate and the side of the second prescribed substrate may be the sides of a common substrate which are opposite to each other.
In the preferred embodiment, the first prescribed substrate may be a substrate different from the second prescribed substrate, the other side opposite to the side of the first prescribed substrate may be bonded to the other side opposite to the side of the second prescribed substrate each other.
In the preferred embodiment, the common substrate may be an Si substrate, and a distance defined between the optical fiber for light transmission and the optical fiber for light reception may be allowed to coincide with a distance between the optical fibers required for the optical connector.
In the preferred embodiment, the first and second prescribed substrates may be Si substrate and a distance defined between the optical fiber for light transmission and the optical fiber for light reception may be allowed to coincide with a distance between the optical fibers required for the optical connector.
In the preferred embodiment, surfaces of the first and second prescribed substrates may be metallized.
In the preferred embodiment, the surfaces metallized may be conductive so as to be capable of ground connection.
In the preferred embodiment, one or both of the sides of the first and second prescribed substrates may be bonded to a surface of a prescribed package.
In the preferred embodiment, the surface of the package is conductive to be grounded.
In the preferred embodiment, the molded optical connector may be provided on the side surface thereof with guide pins for positioning the optical fibers for transmission and reception.